WO2018077934A1 - Machine with a system for axial blocking of the shaft - Google Patents

Abstract

The present invention concerns a rotary machine (1) comprising: ‐ at least one bearing mount (20); ‐ at least one bearing (10) carried by the bearing mount (20), the bearing comprising inner (11) and outer (12) races and rolling elements (13) between the races; ‐ a shaft (2) engaged in the bearing, axially blocked relative to the inner race; ‐ a pushrod cover (30) arranged on one side of the bearing, having a surface (31) opposite the bearing and having, on its radially outer edge, a bead of material (33) in contact with the outer race (12); ‐ at least one push element (40) moveable transversely to the axis of rotation (X) of the shaft (2) in order to exert a pressure on said surface (31) of the push rod cover in order to press it against the outer race (12) and axially block said outer race.

Description

 MACHINE WITH AXIAL LOCKING SYSTEM FOR THE TREE

The present invention relates to rotating machines having a shaft engaged in at least one bearing carried by a bearing, and more particularly but not exclusively rotating electrical machines such as motors or alternators.

 It may be necessary to axially lock a bearing in the corresponding bearing.

 JP S59 53053 A discloses a device for adjusting the axial position of a rotary shaft after assembly in an electric motor.

 US 5,001,377 A discloses a lubrication system for anti-friction bearings supporting a rotating shaft in an electric motor.

 DE 198 24 382 A1 discloses a worm gear unit having at least one worm shaft movable in the axial direction.

 US 3,147,050 A discloses bearing mounting means for a rotating machine for maintaining a bearing in its housing.

 A first way of proceeding consists, as illustrated in FIGS. 1 and 2, in axially locking the bearing 110 by means of a circlip 104 at the level of the inner ring 111 and introducing an elastic pin 130 into a bore of the bearing 120 to axially lock the outer ring 112. A specific piece 140 held by screws 150 is added to protect the bearing 110 against the penetration of external particles and / or to prevent the grease from coming out and pollute surrounding areas.

 Such a solution can be difficult to implement under a small footprint. In addition, it is difficult to control the thrust exerted by the elastic pin on the outer ring 112 and the axial locking force thereof.

 Another way of doing, illustrated in Figure 3, is to fix a part 160 called "cap" on the bearing 120 with the axis of screws parallel to the axis of rotation of the shaft.

 In this case, the control of the axial pressure of the cap 160 on the bearing, combined with the protection of the bearing, is an operation that can be tricky or expensive.

 There is therefore a need to benefit from a solution that reliably ensures the axial locking with the required force of a bearing, and the protection thereof, even in a small footprint.

The invention achieves this objective thanks to a rotating machine comprising: - at least one landing,

 at least one bearing carried by the bearing, the bearing comprising inner and outer rings and rolling elements between the rings,

 a shaft engaged in the bearing, blocked axially relative to the inner ring,

 a pusher cover disposed on one side of the bearing, having a surface opposed to the bearing,

 - At least one thrust element displaceable transversely to the axis of rotation of the shaft for applying a stress on said surface of the pusher cover to press against the outer ring and block the latter axially.

 Thanks to the invention, the thrust member acts by wedge on the pusher cover and the thrust exerted by the pusher cover on the bearing can be more easily controlled, while protecting the bearing.

 Preferably, the or each thrust element is a screw. The thrust exerted by the pusher cover on the bearing can then be easily controlled by screwing the screw more or less, and by controlling the tightening torque of the screw for example.

 Preferably, the or each thrust element is oriented perpendicular to the axis of rotation of the shaft. This facilitates access to the push member and can easily achieve the desired corner effect. This may also allow the realization of a compact machine at the means implemented to ensure the axial locking of the shaft.

 It may be advantageous for said surface to extend obliquely relative to the axis of rotation of the shaft, preferably being conical flaring towards the bearing.

 In this case, the thrust element preferably has a slope at its end which is substantially equal to that of said surface in the zone of support of the thrust element on said surface, the thrust element then being of preferably constituted by a conical tip screw.

 The pusher cover may have on its radially outer edge a bead of material bearing against the outer ring. The face of this bead bearing on the outer ring of the bearing preferably has a shape that matches that of the face facing the outer ring.

The number of pushing elements is preferably at least two, so as to distribute the clamping force on the periphery of the outer ring. Pushing elements are preferably, in this case, diametrically opposed. More preferably, the thrust members are at least three in number, being uniformly distributed at the periphery of the outer ring.

 The pusher cover may have on its radially inner edge a return directed towards the radially inner ring. The pusher cover preferably extends with a small clearance away from the shaft, so as to retain the grease and effectively protect the bearing. This game is for example less than or equal to 1mm. There may be, if necessary, an additional rubbing seal, of the lip ring type or the like.

 The outer ring can be immobilized axially by any means on the opposite side to the pusher cover, and for example the outer ring comes axially in abutment against a shoulder of the bearing on the opposite side to the pusher cover.

 The machine may have a second cover, on the opposite side to the pusher cover, to protect it and retain the grease.

 The pusher cover may be made of any suitable material, in particular plastic, composite or metal, in particular aluminum. The pusher cover is preferably designed not to deform when applied against the outer ring.

 The machine according to the invention can constitute a motor, an alternator or a reducer.

 The invention also relates to a method for axially immobilizing the shaft of a machine according to the invention, as defined above, comprising the step of moving the thrust element or elements relative to the bearing to bring the pusher cover to press the outer ring of the bearing and to immobilize the latter axially relative to the bearing.

 The or each thrust element is preferably screwed into the bearing to apply the pusher cover against the outer ring. Preferably, the tightening torque of the screw is controlled. This makes it easy to control the axial locking force exerted by the pusher cover on the outer ring of the bearing.

 Other characteristics and advantages of the present invention will appear on reading the detailed description which follows, of an example of non-limiting implementation thereof, and on examining the appended drawing, in which:

 FIGS. 1 and 2, previously described, are schematic and partial axial sections of a machine according to the prior art,

FIG. 3 is a view analogous to FIGS. 1 and 2 of an alternative embodiment according to the prior art, and - Figure 4 shows in axial section, schematically and partially, an example of a machine made according to the invention.

 The machine 1 according to the invention, partially shown in FIG. 4, comprises a shaft 2 rotating about an axis of rotation X.

 The machine 1 is for example an electric motor.

 The shaft 2 is engaged in a bearing 10 comprising an inner ring 11, an outer ring 12 and rolling elements 13 arranged between the rings 11 and 12.

 In the example considered, the rolling elements 13 are rollers but the invention is not limited to a particular type of bearing, and the rolling elements may be balls.

 The inner ring 11 is immobilized axially on the shaft 2 by circlips 3 and 4 fixed in corresponding grooves 5 and 6 of the shaft 2. In variants, the immobilization is done differently, for example by a shoulder on the tree.

 The outer ring 12 is carried by a bearing 20 of the machine, having an opening through which the shaft.

 The bearing 20 has a housing 21 in which is received the outer ring 12 of the bearing 10. The housing 21 has a shoulder 23 against which bears axially the outer ring 12.

 A pusher cover 30 is disposed on the opposite side to the shoulder 23 to press the outer ring 12 against the shoulder 23.

 This pusher cover 30 has a wall 31 of conical shape, converging away from the shoulder 23, extending substantially over the entire radial dimension of the space between the bottom 21a of the housing 21 and the shaft 2.

 The pusher cover 30 has on its radially outer edge, on the side of the shoulder 23, a bead of material 33 and on its radially inner edge a return 34 directed towards the bearing 10, extending substantially parallel to the axis X.

 The bead 33 bears axially against the outer ring 12 on the side opposite to the shoulder 23.

 Several thrust elements, constituted by screws 40, only one of which is visible in FIG. 1, are arranged on the bearing 20 so as to exert stress on the thrust plate 30 to press it against the bearing 10.

The screws 40 are screwed into corresponding threads 29 of the bearing 20, distributed uniformly, oriented perpendicularly to the axis X, and each have a conical tip 41 of the same conicity as the surface 35 of the wall 31 opposite the bearing 10.

 The conical end 41 bears on the wall 31 on the side opposite to the bead 33. By screwing the screw 40, a wedge effect is transmitted by an angular effect to the outer ring 12.

 By more or less screwing the screw 40 and controlling the tightening torque, it is thus possible to precisely control the axial thrust exerted by the pusher cover 30 on the outer ring 12.

 The return 34 extends with a small clearance of the shaft 2, so as to retain the fat present in the space 38 between the bearing 10 and the pusher cover 30.

 On the opposite side to the pusher cover 30, the machine may comprise a cover 50 extending between the bearing 20 and the shaft 2, with a small clearance therewith, as illustrated.

 The cover 50 may comprise a return 51 to the bearing, on its radially outer side, which is immobilized axially between the outer ring 12 and a shoulder 27 of the bearing 20.

 Of course, the invention is not limited to the illustrated example. For example, the machine is a gearbox or an alternator, or any other mechanism where there is an interest in axially locking a shaft guided by at least one bearing.

 In variants, the second cache 50 is absent; in variants also, the machine is made without shoulder 23.

Claims

1. Rotating machine (1) comprising:  at least one bearing (20);  - At least one bearing (10) carried by the bearing (20), the bearing having inner rings (11) and outer (12) and rolling elements (13) between the rings;  - A shaft (2) engaged in the bearing, axially locked relative to the inner ring;  - A pusher cover (30) disposed on one side of the bearing, having a surface (31) opposite to the bearing and having on its radially outer edge a bead of material (33) bearing against the outer ring (12);  at least one pushing member (40) moved transversely to the axis of rotation (X) of the shaft (2) for applying a stress on said surface (31) of the push cover in order to press it against the outer ring ( 12) and lock the latter axially.  2. Machine according to claim 1, the or each push member (40) being a screw.  3. Machine according to claim 1 or 2, the or each thrust member (40) being oriented perpendicularly to the axis of rotation (X) of the shaft.  4. Machine according to any one of the preceding claims, said surface (31) extending obliquely relative to the axis of rotation (X) of the shaft.  5. Machine according to any one of the preceding claims, said surface (31) being conical flaring closer to the bearing (10).  6. Machine according to one of claims 4 and 5, the thrust member (40) having a slope at its end, substantially equal to that of said surface (31) in the bearing zone of the thrust member. on said surface, the thrust member (40) being preferably constituted by a conical tip screw (41), in particular of the same conicity as the surface (31). 7. Machine according to any one of the preceding claims, the pusher cover (30) having on its radially inner edge (34) a return directed towards the radially inner ring (11). 8. Machine according to any one of the preceding claims, the outer ring (12) coming axially bearing against a shoulder (23) of the bearing (20) on the opposite side to the pusher cover (30).  9. Machine according to any one of the preceding claims, comprising a second cover (50) on the side opposite the push cover (30).  10. Machine according to any one of the preceding claims, the pusher cover (30) being made of plastic, composite or metal.  11. Machine (1) according to any one of the preceding claims, constituting a motor, an alternator or a reducer.  12. Machine according to claim 2, the or each thrust member (40) being screwed into the bearing (20) to apply the pusher cover (30) against the outer ring (12).  13. A method for axially immobilizing the shaft (2) of a machine as defined in any one of the preceding claims, comprising the step of moving the or each thrust member (40) transversely to the axis of rotation (X) of the shaft (2), to cause the pusher cover (30) to press the outer ring (12) of the bearing (10) and to immobilize the latter axially relative to the bearing (20).  14. The method of claim 13, the or each thrust member (40) being screwed into the bearing (20) to apply the pusher cover (30) against the outer ring (12).  15. The method of claim 14, the or each thrust member (40) being screwed with a controlled torque.